<div class="tab_box" style="display: block;">

<iframe id="show" src="url1" frameborder="0" allowfullscreen=""></iframe>

<ul class="play">
 <li class="btn" id="url1">Link 1</li>
 <li class="btn" id="url2">Link 2</li>
 <li class="btn" id="url3">Link 3</li>
</ul>

</div>

<script type="text/javascript">
    $(function(){
        $(".btn").click(function(){
        x=$(this).attr('id');
            forOk=x.indexOf("videoembed");
            if(forOk==0)
            {x="//ok.ru/"+x;}
        $(".btn").removeClass('main');
        $(this).addClass( "main" )
        $("#show").attr('src',x);       
        });
    });
</script>

<div id="player"></div>
<script>
   var player = new Playerjs({id:"player", file:"video.mp4"});
</script>